<template>
  <div>
    <h1>{{ message }}</h1>
    <button @click="greet">greet</button>
  </div>
</template>
<script>
export default {
  data() {
    return {
      message: 'Hello.Vue3!'
    }
  },
  methods: {
    greet() {
      this.message = 'Hello,' + this.name + '!' 
    }
  }
}
</script>